Garlic enhances slimming effect of running
Overweight mice can slim down if you let them run daily on a treadmill. If you give them a garlic extract as well then they'll lose even more fat. But how does garlic speed up weight loss? The researchers at Inje University in Korea didn't manage to work that out.
Obesity, inflammation & garlic
If you are too fat, you're in a state of continuous inflammation. Those layers of fat are literally rotting away, and your immune cells are busy clearing up the died-off fat cells. Added to that, inflammatory proteins like interleukin-6, tumor necrosis factor-alpha and C-reactive protein are being released. These do all sorts of unhealthy things in your body, one of which is that they stimulate the growth of fat tissue.
Garlic extracts contain compounds such as gamma-glutamylcysteine, S-allylcysteine [structural formula shown here], S-allylmercaptocysteine and S-methylcysteine. These inhibit the production of inflammatory factors, so you'd expect them to have an anti-obesity effect.
The Koreans decided to find out whether this is indeed the case. At the cost of the Korean government they fattened a group of lab rats for six weeks, using a high-fat diet [HFD] and gave a control group ordinary feed [ND]. After that the real experiment started, and continued for 4 weeks.
The Koreans let one group of rats continue to fatten [HFD] and gave another group 2.8 g Aged Garlic Extract per kg bodyweight every day [HFD+AGE]. The supplement was given orally. The extract came from the Uiseong Black-Garlic Farming Association of Korea, but as far as we can tell from reading the article this organisation did not fund the research.
Another group of rats had to run on a treadmill five days a week [HFD+Exercise]. The researchers gradually increased the intensity of the exercise each week.
A fourth and final group of rats had to run and were also given the garlic extract [HFD+Exercise+AGE]. They were given the extract half an hour before they were put on the treadmill.
The figure and table below show that garlic and exercise mutually reinforced each other's slimming effect. Click on the tables for larger versions.
The table above shows that the rats in the HFD+Exercise+AGE group started to eat less. But that doesn't explain why the animals in this group lost weight more quickly than the animals in the HFD+Exercise group. The food-efficiency ratio decreased as a result of the combination of running and garlic supplementation. That means that the rats grew less with the same amount of food.
How that happened the Koreans don't understand, as their theory didn't hold water. They observed no effect of the garlic extract on the inflammatory proteins mentioned above. The concentration of triglycerides in the blood of the rats in the HFD+Exercise+AGE group declined considerably. Apparently the combination of a garlic supplement and exercise does something to fat metabolism. We hazard a guess, in one word: UCPs.
"Aged Garlic Extract with exercise is more effective in controlling obesity than either intervention alone", the Koreans write. "However, more extensive research is needed before recommending Aged Garlic Extract supplementation to obese humans."
Nutr Res Pract. 2012 Dec;6(6):513-9.
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